How we calculate

Yearly figures, not pay periods

Our calculators work out tax, National Insurance and student loan repayments on a whole year's income. Real payroll (PAYE) works each pay period separately, using weekly or monthly thresholds; for National Insurance, the period is the interval you are paid at (HMRC National Insurance manual NIM08020). So your payslips can differ slightly from our yearly figures.

One example: when employers work out student loan repayments, they round each deduction down to a whole pound every pay period (HMRC student loan deduction tables). We work in pounds and pence across the year, so our yearly repayment can be a few pounds higher than the total on your payslips.

Pay that changes during the year, such as a bonus, overtime or starting a job part-way through, can also make PAYE differ from a yearly estimate.

How take-home pay is worked out

The salary calculator follows these steps, in this order.

1. Pension contributions

Salary sacrifice: your salary is reduced before anything else, so you pay no income tax, National Insurance or student loan repayment on the amount you sacrifice.
Net pay arrangement: your contribution is taken before income tax, so you get tax relief straight away. National Insurance and student loan repayments are still worked out on your full salary.

Relief at source pensions, where your provider claims the tax relief, are not included in our calculators.

2. Personal Allowance

Most people can earn £12,570 a year before paying income tax. If your income is over £100,000, your allowance goes down by 50% of every pound above that level, until it reaches zero. We use the income after any pension contribution for this test. We assume the standard tax code and no other income.

3. Income tax

Income above your allowance is taxed in bands. The band limits below are amounts of taxable income, which is income after your Personal Allowance. They stay the same even when your allowance is reduced.

England, Wales and Northern Ireland, 2026/27
Band	Taxable income	Rate
Basic	Up to £37,700	20%
Higher	Up to £125,140	40%
Additional	Over £125,140	45%

Scotland, 2026/27 (wages, pensions and other non-savings income)
Band	Taxable income	Rate
Starter	Up to £3,967	19%
Basic	Up to £16,956	20%
Intermediate	Up to £31,092	21%
Higher	Up to £62,430	42%
Advanced	Up to £125,140	45%
Top	Over £125,140	48%

GOV.UK also shows these bands as ranges of total income. Those ranges assume you get the full Personal Allowance, so they do not apply once your allowance starts to fall.

4. National Insurance

Employees pay Class 1 National Insurance of 8% on earnings between £12,570 and £50,270 a year, and 2% on earnings above that. We use the standard category of National Insurance and do not include what your employer pays.

5. Student loans

Repayments are a share of your earnings above a yearly threshold. They are worked out on the same pay that National Insurance uses.

Student loan repayments, 2026/27
Plan	Yearly threshold	Rate above it
Plan 1	£26,900	9%
Plan 2	£29,385	9%
Plan 4 (Scotland)	£33,795	9%
Plan 5	£25,000	9%
Postgraduate	£21,000	6%

If you have more than one undergraduate plan, you make one repayment, worked out on the lowest threshold of your plans. A Postgraduate Loan repayment is added on top of any undergraduate repayment.

6. Take-home pay

Take-home pay is your salary minus income tax, National Insurance, student loan repayments and pension contributions.

Rounding

We do every calculation at full precision and round each total to the nearest penny only at the end, rounding halves up. Take-home pay is then your salary minus those rounded amounts, so the breakdown always adds up exactly.

Monthly, weekly, daily and hourly figures

These are the yearly figures divided evenly:

Monthly: divided by 12.
Weekly: divided by 52.
Daily: divided by 260 working days (five days a week).
Hourly: divided by your hours a week times 52. If you do not enter your hours, we use 37.5 hours a week.

For the Child Benefit tax charge, we estimate a year of Child Benefit as 52 weeks at the weekly rate. The real charge is based on the Child Benefit actually paid to you in the tax year, which depends on payment dates. Some tax years have 53 payment weeks, so the real charge may be slightly higher.

What we leave out

To keep the calculators clear, some things are not included. Any of them can change your real figures:

tax codes other than the standard one, including codes for benefits in kind or underpaid tax;
income other than your salary in the salary calculator, such as savings interest, rent or self-employed profits;
Marriage Allowance, Blind Person's Allowance and other reliefs;
relief at source pension contributions;
National Insurance categories other than the standard one, and the National Insurance your employer pays;
the effect of pay that changes during the year.

Keeping figures up to date

Each tax year runs from 6 April to 5 April and has its own set of figures. Every figure is stored with the GOV.UK or HMRC page it comes from and the date we checked it. The last full review of the 2026/27 figures was on 29 September 2026. Between full reviews, an automatic check confirms the wording is still on each source page (see below).

When the Budget announces changes, we add the next year's figures, check each one against the primary source, and test the calculators again. The site switches to the new figures on 6 April.

Automatic source checks

Each calculator says when its figures were last checked against GOV.UK. Two kinds of check sit behind that date.

The full review. A person reads each source page and confirms every figure, and how it is used, by hand. For 2026/27 this was last done on 29 September 2026.
The automatic check. For most figures we have copied a short piece of exact wording from its source page, such as the line in a table that shows a rate. A small program fetches each source page and looks for that wording. If every piece is still there, the date moves forward. If any piece is missing, or a page cannot be reached, the date stays where it was until we have looked into it.

The last automatic check in which every checked figure passed was on 8 October 2026. It covered 81 of the 95 figures we use. The rest are rules described in words, such as who counts as a first-time buyer, which have no single line of text to look for. Those are covered by the full review only.

What the automatic check does not prove:

It shows that the wording is still on the page. It does not show that we use the figure correctly; our tests and the full review do that.
It cannot spot a new rule that GOV.UK adds somewhere else, or a change announced but not yet on the page.
We run it by hand, not on a fixed timetable, so the date can be some days old.

Sources

These are the GOV.UK and HMRC pages our 2026/27 figures are checked against:

Corrections

When we fix a mistake that changed a result, we list it here with the date. No corrections have been needed so far. See our corrections policy.